It's worth noting that this is a tiny, tiny amount of money by US standards. A couple billion USD is not a big deal (financially or militarily, other than as a signal).
Still, as a Japanese resident, I am happy with this use of my tax money. With the Cold War with China already well underway, I think Japan needs a much stronger military than at any time since losing WWII. Partly because of the economic ascendance of China (which a lot of people these days somehow forget is a brutal, repressive, totalitarian state, not an advanced democracy like Japan) and partly because of the decline of the USA as comptent and rational actor on the world stage. Treaty-bound or not, I don't have much faith that the USA would do much wrt Chinese aggression toward Japan, short of an actual invasion (which hopefully will remain very unlikely).
Still, as a Japanese resident, I am happy with this use of my tax money. With the Cold War with China already well underway, I think Japan needs a much stronger military than at any time since losing WWII. Partly because of the economic ascendance of China (which a lot of people these days somehow forget is a brutal, repressive, totalitarian state, not an advanced democracy like Japan) and partly because of the decline of the USA as comptent and rational actor on the world stage. Treaty-bound or not, I don't have much faith that the USA would do much wrt Chinese aggression toward Japan, short of an actual invasion (which hopefully will remain very unlikely).